1. Field of the Invention
The present invention relates to an air conditioning control system which utilizes a fuel cell.
2. Description of the Related Art
At low temperatures, fuel cells do not generate sufficient power. To attempt to address this problem, there is a technique in which fuel cells are warmed by using the electric power of the fuel cell to heat a liquid coolant when the fuel cell is at a low temperature, such as when activating the fuel cell. To maintain the fuel cell at a specific temperature appropriate for operation, a fuel cell system also includes a cooling device for circulating the coolant to dissipate undesired heat generated in the fuel cell by a radiator.
On the other hand, moving objects which utilize the fuel cell as a power source (e.g., hybrid or electric vehicles or the like) include an air conditioning control device for heating and cooling the passenger compartment or interior of the vehicle. An example of such an air conditioning device would be a vapor compression heat pump which transfers heat from the lower temperature side to the higher temperature side.
Other techniques have also been proposed for utilizing or dissipating heat generated in the fuel cell system in the air conditioning device. For example, in one technique, heat generated in a fuel cell stack is collected by a heat exchanger for heating, and the collected heat is utilized as a heat source for a heater. In the air conditioning device for vehicles, where the vehicle interior can be heated by running the cooling liquid of the fuel cell through a heater core, when the unnecessary heat generated in the fuel cell is insufficient for the required amount of heat necessary for air conditioning, another technique may be used to control the generation of heat to compensate for the shortage of heat. In a still another technique, an extra heat drained from the fuel cell itself may be dissipated into the air by a radiator disposed in the air conditioning system. Further, there is a system for heating the cooling fluid of the fuel cell by an extra power generated in regenerative braking, where the extra power is consumed while utilizing the heat of the cooling liquid of the fuel cell for air conditioning.